Production of polymerization products



Patented Dec. 13, 1938 UNITED STATES PATENT OFFICE PRODUCTION OFPOLYMZERIZATION PRODUCTS No Drawing. Original application January 17,

1931, Serial No. 509,532.

Divided and this application May 4, 1937, Serial No. 140,690. In GermanyJanuary 28, 1930 9 Claims.

The present invention relates to the production of polymerizationproducts and articles therefrom.

We have found that the polymerization of water-insoluble carboxylderivatives of acrylic acid and its homologues, such as acrylic methyl,ethyl or amyl or aromatic esters, acrylic nitrile, acrylic anilide ora-methylacrylic butyl ester, is advantageously carried out byemulsifying the said substances as such, or in admixture with each otheror with other substances, in liquids in which the said initial materialsare practically insoluble, such as water or aqueous liquids, and thenpolymerizing them. In this manner from latex-like liquids to solidproducts are obtained,

the latex-like liquids yielding very valuable products of great purity,those obtained from acrylic esters, resembling first quality Indiarubber when,

coagulated.

The emulsions are preferably prepared with the aid of emulsifying agentssuch as Marseilles soap, ammonium oleate or Turkey red oil oremulsifying Wetting agents, 1. e., true sulphonic acid salts, such asalkylated naphthalene sulphonic salts or palmitic sulphonic salts, orboth emulsifying and wetting agents.

The thinly liquid emulsions may be obtained in a stable form even byshaking, but they may also be prepared in suitable emulsifyingapparatus, as for example homogenizers. In this form they are extremelystable to the saponifying actions of the water. The polymerization,which may be carried out by known methods either in the cold or whileheating to any temperatures up to the boiling point of water, or in aclosed vessel, somewhat above the boiling point of water and at a fewatmospheres above atmospheric pressure, say at 2, 3 or about 5atmospheres may be accelerated by irradiation with artificial or naturalsources of light and/or by the employment of polymerizing agents such ashydrogen peroxide, ozone, benzoyl peroxide, sodium para-toluenesulphonic chloramide and the like, depending on the nature of thestarting materials, the acrylic esters being usually more easilypolymerized than the nitrile, the polymerization of which latter ispreferably carried out at from 60 to 80 C; in the presence of aperoxide.

Valuable mixed polymerization products are obtained by polymerizing thesaid initial materials in the emulsified form in admixture with eachother or with other organic substances capable of forming films, or atleast capable of forming film-forming polymers, such as vinyl acetate,vinyl chloride or styrene which apparently also accelerate thepolymerization of the acrylic derivatives. Thus acrylic nitrile, acrylicamides or their derivatives, aliphatic or aromatic esters of acrylicacid may be polymerized in any desired mixtures and/or in conjunctionwith vinyl acetate, or chloride, with styrene and so on, the number ofpossible'variations being extremely high owing to the possibility ofemploying any desired concentration of the ingredients preferably whileemploying preponderating, or at least equal quantities of acrylicderivatives; especially styrene, which is capable of forming hardpolymers, is employed in quantities lower than those of thewater-insoluble acrylic derivatives employed. Valuable masses are alsoobtained by adding organic film-forming substances which are notthemselves polymerizable, as for example cellulose derivatives, India orlike vegetable rubber, artificial resins as for examplepara-toluenesulphonamide formaldehyde resins, polymerized styrenes orpolymerized vinyl acetate and the like or softening agents such ascamphor, phenols, phthalic esters, phosphoric esters, derivatives ofurea or like known plasticizers, before, during or after thepolymerization, the cellulose derivatives, rubber or polymerizedsubstances being preferably dissolved in the acrylic derivatives beforethe emulsification if the said additions be made before or during thepolymerization. For the sake of brevity the said additional substanceswill be comprised in the following and in the claims by the term organicfilm-forming substances.

A particularly eiiicient method of polymerization is carried out in sucha manner that the said acrylic acid derivatives or their homologues,either alone or in admixture with each other or with other substanceswhich may be polymerizable, are slowly introduced, as for example byspraying them in fine jets or allowing them to run or drop in, intoaqueous solutions of emulsifying and/or wetting agents while vigorouslystirring or whirling and while heating and/or irradiating. The speedwith which the materials to be polymerized are introduced depends" onthe nature of the substances or mixtures to be polymerized, on thetemperature of the solution, on the intensity of the irradiation and onthe nature of the emulsifying agents and wetting agents. It may beincreased by the addition of polymerization accelerators, as for examplehydrogen peroxide, benzoyl peroxide and the like. The polymerizing agentmay be added to the aqueous solution or to the substance to bepolymerized or to both. The final polymerization products are obtainedin the form of latex-like dispersions, powders or lumps according to theparticular conditions of working,

The mixed polymerization products are especially valuable and have quitedifferent properties from the mixtures of products prepared from thesingle. components by separate polymerization.

The products according to the present invem tion may be employed for themost varied purposes and in any desired combination, depending on thedesired choice of the initial materials such as acrylic nitrile, acrylicesters or amides either solely or in mixture with each other or withother unsaturated polymerizable compounds such as acrylic acid, vinylacetate, vinyl chloride or styrene. By combination of the polymerizedesters or of mixtures thereof with derivatives of cellulose, such asnitro cellulose, cellulose carboxylates or ethyl cellulose, highlyelastic films can be obtained which are stable to repeated bending.Films of the polymerized esters and particularly films from the estersof acrylic acid with alcohols of low molecular weight, such as frompolymerized acrylic methyl ester, can be employed for many purposeswithout any addition and may be employed for example as adhesives in theproduction of safety glass or as coatings on leather or fabrics.Mixtures from polymerized acrylic nitrile and/or acrylic esters on theone hand and vinyl chloride or styrene on the other hand furnishparticularly strong products which are, however, still highly elasticand may be advantageously worked into films, threads or coatings; whenthe said mixtures contain about per cent or more by weight of the vinylchloride or styrene, valuable artificial masses can be obtainedtherefrom by pressing the products possessing a very high electricalinsulating power and a high strength.

The polymerization products obtainable in accordance with the presentinvention are superior to those hitherto prepared by polymerizing theacrylic derivatives in non-emulsified state; they are much morehomogeneous and free from monomeric constituents and from any bad smelladhering to the hitherto known products. Besides this the r solutionspossess a higher relative viscosity, w ch is generally at least fivetimes, and even substantially more than, that of the hitherto knownproducts. Thus for example a 5 per cent solution in butyl acetate of apolymeric acrylic ethyl ester obtainable in accordance with the presentinvention shows a relative viscosity of about 500 when determined in anUbbelohde viscosimeter at 25 C., a solution of the same concentration ofa polymeric acrylic ethyl ester prepared by direct polymerizationshowing a relative viscosity of about 60 only. The ratio of viscositiesof polymeric acrylic ethyl esters is about 110 to about 950. Ifproducts, the solutions of which have a higher viscosity are desired bydirect extended polymerization, the solubility is reduced and theproducts become insoluble and swell in organic solvents withoutdissolution. The mixed polymerization products possess the particularadvantage and typical property of being plastic while hot and ofpossessing a high hardness and strength at normal temperatures, whereasthe polymerlzation products from acrylic esters alone resemble Indiarubber. Besides this the process according to the present invention doesnot require special and costly apparatus and allows of easily removingthe products from the reaction vessels and of obtaining thepolymerization products entirely free from monomeric initial material.

The following examples will further illustrate the nature of thisinvention, but the invention is not restricted to these examples. Theparts are by weight.

Example 1 100 parts of pure acrylic ethyl ester are emulsifled in 200parts of water containing 0.3 per cent of Marseilles soap, 0.5 per centof propyl naphthalene sulphonic sodium salt and 2 per cent oi 30 percent aqueous hydrogen peroxide, and the is excellently soluble in theusual organic solvents,.

as for example in chlorinated hydrocarbons such as chlorbenzene,ketones, such as acetone or cyclohexanone, and esters, to give veryviscous solutions from which elastic and strong films may be prepared bythe incorporation with nitrocellulose.

Example 2 100 parts of acrylic ethyl ester are emulsified in 200 partsof water containing 1 per cent oi the mono oleic ester of triethanolamine. The emulsion is heated while stirring for 12 hours at from 80 toC. under a reflux condenser, whereby, especially on a large scale,external heating may be temporarily superfluous by reason of the heat ofthe reaction, and in some cases it may be even necessary to cool thewhole to the said temperature. The dispersion is freed from the lasttraces of non-polymerized ester with the aid of steam and coagulated asdescribed in Example 1. The product has an excellent solubility inacetone, ethylene glycol monoethyl ether acetate, ethyl butyl orbenzylacetates, chlorbenzene, dioxaneand the like, and a high viscosity.

Example 3 Example 4 parts of styrene and 100 parts 01! acrylic ethylester are emulsified in' 400 parts of water which has been incorporatedwith 0.5 per cent of Turkey red oil and 0.25 per cent of isobutylnaphthalene sulphonic sodium salt. After 26 days the liquid yields, whenpoured into aqueous 5 per cent hydrochloric acid a coagulate which issoluble in the'usual organic solvents, such as benzene or butyl acetate,to give very viscous solutions. By pressing and heating, sheets, slabsand other artificial masses may be prepared from the prod- Example 5 100parts of acrylic ethyl ester are emulsified in 200 parts of water towhich 0.3 per cent 0! Mar- Example 6 20 parts of nitrocellulose aredissolved in 80 parts of acrylic ethyl ester and emulsified in 200 partsof water which contain 0.3 per cent of Marseilles soap and 0.5 per centof sodium isopropylnaphthalene sulphonate and which has been adjustedwith the aid of N/100 aqueous sulphuric acid to a hydrogen ionconcentration corresponding to a pH value of 6.2. 2.5 parts of 30 percent aqueous hydrogen peroxide are added to the emulsion. After heatingfor 2 hours at from 80 to C., the dispersion is freed from anynon-polymerized ester with the aid of steam, and coagulated with the aidof aqueous 5 per cent hydrochloric acid. The product is readily solublein organic solvents and yields very elastic films.

Example 7 100 parts of a-methyl acrylic butyl ester in which 0.75 partof benzoyl peroxide has been dissolved are emulsified in a solution of1.5 parts of Turkey red oil and 0.75 part of the sodium salt ofiso-butyl naphthalene sulphonic acid in 300 parts of Water. The emulsionis then heated under reflux, while stirring, to from 80 to C. for from 2to 5 hours. By treatingthe polymerization product with steam, the lasttraces of the monomeric acrylic esters are removed and thepolymerization product can be coagulated with the formation of a productresembling raw rubber by the addition of 3 parts of concentratedhydrochloric acid.

Example 8 parts of (monomeric) acrylic nitrile are emulsified in anaqueous solution of 0.5 part of the sodium salt of palmitic sulphonicacid and 0.6 part of Marseilles soap in 200 parts of water. The emulsionobtained is incorporated with 3 parts of aqueous 30 per cent hydrogenperoxide and then heated in a stirring vessel provided with a refluxcondenser for from 2 to 5 hours at the start to from 70 to 80 C. andfinally to 90 C. The polymerization product formed is mainlyprecipitated during the polymerization in the form of a white powder andsmall lumps and is freed from the last traces of monomeric acrylicnitrile by introducing steam after the polymerization has been finished.The polymerization product. can be moulded by pressing into artificialmasses of high insulating power and stability against water.

Example 9 0.75 part of benzoyl peroxide is dissolved in a mixture of 20parts of (monomeric) acrylic nitrile and 80 parts of (monomeric) acrylicethyl ester which solution is then converted into a milky emulsion byshaking it with a solution of 1 part of Turkey red oil and 0.5 part ofthe sodium salt of iso-butyl naphthalene sulphonic acid. By heating theemulsion for from 2 to 5 hours from 70 to 90 C., a mixed polymerizationproduct of the nitrile and of the ester is obtained some portion of thepolymerization product being already precipitated in the coagulatedform. In order to complete the coagulation 2 parts of concentratedhydrochloric acid are added, whereby a product is obtained whichresembles in some degree raw rubber the hardness of which product,however, is I greater than that of a polymerization product from pureacrylic ethyl ester; the product obtained is soluble in acetone,cyclohexanone and other organic solvents and furnishes transparent softfilms which may be employed as an adhesive in the production of compoundglass from several glass plates.

' Example 10 0.75 part of benzoyl peroxide is dissolved in a mixture of90 parts of (monomeric) acrylic nitrile and 10 parts of (monomeric)acrylic methyl ester, whereupon the solution is emulsified in a solutionof 1 part of Turkey red oil and 0.5 part of the sodium salt of di-isobutyl naphthalene sulphonic acid in 200 parts of water; the emulsion isthen heated for 4 hours at from 70 to 90 0., whereby a completepolymerization is attained and the product is then coagulated by addingat room temperature 3 parts of concentrated hydrochloric acid. The hardproduct obtained dissolves only in concentrated acids, for example inphosphoric acid, with simultaneous saponiflcation and is suitable forthe production of artificial masses by pressing, the articles obtainedpossessing a high insulating power and a good resistance to bending.

Example 11 0.5 part of benzoyl peroxide is dissolved in a mixture of 60parts of (monomeric) acrylic nitrile and of 40 parts of (monomeric)vinyl acetate,

Example 12 40 parts of (monomeric) acrylic nitrile and 60 parts of(monomeric) styrene are emulsified in a solution of 1 part of Turkey redoil and 0.5 part of the sodium salt of iso-butyl naphthalene sulphonicacid in 200 parts of water; 3 parts of aqueous 30 per cent solution ofhydrogen perox ide are then added and the polymerization is per-' formedby heating for 2 /2 hours at from 70 to 90 C. The mixed polymerizationproduct is precipitated during the polymerization as a soft mass whichbecomes hard on cooling to room temperature.

Example 13 A mixture of 60 parts of (monomeric) acrylic nitrile, 30parts of (monomeric) acrylic methyl ester and 10 parts of styrene isemulsified in a solution of 1.5 parts of Turkey red oil and 0.75 part ofthe sodium salt of butyl naphthalene sulphonic acid in 300 parts ofwater. The emulsion is then heated in a pressure tight stirring vesselfor 1 hour to from 100 to 0., whereby a liquid resembling rubber latexis obtained which is converted into a hard but elastic product by adding5 parts of hydrochloric acid. Artificial threads may be obtained fromthe said product by spinning a solution of the coagulated product inacetone through spinning nozzles in the man-' o quent bending.

Example 14 A mixture of 50 parts of (monomeric) acrylic ethyl ester andof 50 parts of a 70 per cent solution of (monomeric) acrylic acid isemulsified in a solution of 0.15 part 01' Marseilles soap, 0.5 part oitriethanol amine mono oleic ester and 2.5 parts of per cent aqueoushydrogen peroxide in 150 parts of water, and the emulsion is then heatedfor 2 hours at from 75 to 90 C. Aiter treating the polymerizationproduct obtained with steam a hard elastic mass is obtained.

Example 15 5 parts of the polymeric soluble acrylic methyl ll ester and5 parts of nitrocellulose are dissolved A 16 per cent solution inacetone of equal parts of polymeric acrylic ethyl ester and of anitrocellulose employed for the production of films is spun through atower of about 1.2 metres height, heated to 85 C. through spinningnozzles at a pressure of 8 atmospheres and a velocity of drawing oil.the threads at 137 metres per minute. Threads of 1.6 denier with a goodstrength and tensile elasticity are obtained. The finished threads canbe denitrated in the manner usually applied in the denitration ofnitrocellulose threads and they are superior to threads from viscose asregards elasticity and strength on fre- Eazample 17 parts of acyrlicnitrile and 60 parts of acrylic methyl ester are mixed with 20 parts ofcamphor,

0.2 part of benzoyl peroxide, and the whole is emulsified in a solutionof 2 parts of Turkey red oil, 1 part oi iso-butyl naphthalene sulphonicacid sodium salt and 2 parts of an aqueous 30 per cent solution ofhydrogen peroxide in 400 parts of water.

The emulsion is then heated in a closed vessel to from 90 to 95 C. andthe polymerization is completed after from 15 to 30 minutes, a latexlikeproduct containing small quantities of solid matter being obtained. Byadding 2 parts of concentrated hydrochloric acid coagulation takesplace. The final product is a thermoplastic mass which is hard in thecold state and can be easily pressure moulded, worked with metal toolsor blown into moulds like Celluloid. In the place of 50 camphor phenol,tricresyl phosphate, di-butyl phthalate or diphenyl', dimethyl urea maybe employed.

Example 18 A solution of 2 parts of sodium iso-butyl naphthalenesulphonate, 4 parts of Turkey red oil and 12 parts of 30 per centaqueous hydrogen peroxide in 400 parts of water is heated to from 90 to95 C. in a vessel provided with a reflux condenser. 100 parts ofmonomeric acrylic nitrile are allowed to drop in slowly while stirringvigorform, a white pulp being formed. Any non-polymerized nitrile can beremoved therefrom by treatment with steam and the pure polymerizationproduct is isolated by filtration by suction.

Example 19 A solution of 0.3 part of sodium oleate, 1 part oftrimethanolamlne mono-oleic ester and 3 parts of 30 per cent hydrogenperoxide in 400 parts of water is heated to from 85 to 95 C. in a vesselprovided with a refiux condenser. 100 parts of pure monomeric acrylicethyl ester are allowed to drop slowly into the mixture while stirring.The temperature fallsto from 75 to C. and rises again to 90C. towardsthe end. The polymerization product largely remains emulsified likerubber latex and is precipitated by treatment with steam as arubber-like mass which forms very viscous solutions when dissolved inorganic solvents, as for example benzene, acetone or butyl acetate.

Example 21 A solution of 0.6 part of Marseilles soap and 2 parts ofTurkey red oil in heated to 90 C. and 100 parts of pure monomericalpha-methylacrylic butyl ester containing 1 part 01 benzoyl peroxidedissolved therein are allowed to drop in while stirring. After thetemperature has fallen at the start to about 80 C. it rises again to 90C. towards the end. The polymerization product which is immediatelyformed is freed from the last traces of monomeric ester by vigorouslyboiling the dispersion and is then wholly coagulated by the addition of4 parts of concentrated hydrochloric acid.

Example 22 A mixture of 50 parts of acrylic methyl ester, 50 parts ofacrylic ethyl'ester and 1 part of acetic anhydride is sprayed in finejets into a vessel providedwith a reflux-condenser and containing asolution of 0.6 part of Marseilles soap, 2 parts of Turkey red oil and 3parts of 30 per cent hydrogen perioxide in 300 parts of water which isat first heated to from 75 to 80 C. and towards the end to 90 C. Thepolymerization takes place very rapidly during the spraying. Thepolymerization product remains largely emulsified like rubber latex andmay be completely coagulated to a rubber-like mass soluble in organicsolvents by blowing with steam or, more rapidly, by the addition 01' 5parts of concentrated sulphuric acid. w

- Example 23 A solution of 1 part of Turkey red oil, 0.5 part of sodiumiso-propyl naphthalene sulphonate and 2 parts of 30 per cent hydrogenperoxide in 200 parts of water is heated to from to C. A mixture of 60parts of monomeric acrylic nitrile, 30 parts of monomeric acrylic ethylester and 10 parts of monomeric vinyl acetate is slowly introduced whilestirring. The temperature falls at the beginning to from 70 to 75 C. butrises to 90 400 P 1 5 of water is C. again towards the end. Thepolymerization 75 product which is precipitated in a granular form ispurified by treatment with steam. It is soluble in some organicsolvents, as for example acetone, to give clear solutions.

Example 24 A solution of 0.5 part of sodium iso-butyl naphthalenesulphonate and 1 part of Turkey red oil in 200 parts of water is heatedto 90 C. and 95 parts of monomeric acrylic nitrile containing 5 parts ofchior-ethyl-tri-phosphoric ester and 0.5 part of benzoyl peroxide aregradually introduced, while stirring vigorously. The temperature fallsto from to C. and must be raised to 90 C. towards the end. Thepolymerization product formed is treated with steam. It is a whitepowdery mass.

Example 25 A solution of 0.25 part of the sulphuric ester of octodecylalcohol, 0.5 part of Turkey red oil and 2 parts of 30 per cent hydrogenperoxide in 100 parts of water is heated to from to C. and a mixture of50 parts of acrylic nitrile, 50 parts of a 72 per cent aqueous acrylicacid and 1 part of acetic anhydride is slowly added. The reactiontemperature is initially 76 C. and must be raised to 0. towards the end.The polymerization product formed is soluble in alkalies giving veryviscous solutions.

Example .26

A solution of 0.15 part of Marseilles soap and 0.5 part of Turkey redoil in parts of water is placed into a glass vessel which is exposed tobright sunlight. 100 parts of acrylic ethyl ester containing 1 part ofacetic anhydride and 0.3 part of benzoyl peroxide are allowed to flowslowly from a vessel protected from the light into the glass vesselwhile stirring and the glass vessel is irradiated by the sunlight untilthe polymerization is completed. The polymerization is completed afterseveral hours or after from 1 to 2 days depending on the intensity ofthe light. The insolubility of the polymerization product in organicsolvents, such as acetone and butyl acetate, is a sign of the highdegree of polymerization of this product prepared in sunlight.

This application is a division of our application Ser. No. 509,532,filed January 1'7, 1931.

What we claim is:

1. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues, the step which comprises subjecting topolymerization an emulsion of such nitrile in a liquid in which the saidnitrile is practically insoluble.

2. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues, the step which comprises subjecting topolymerization an emulsion of such nitrile in a liquid containing anemulsifying agent in which liquid the said nitrile is practicallyinsoluble.

3. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues, the step which comprises subjecting topolymerization an emulsion of such nitrile in an aqueous liquid in whichthe said nitrile is practically insoluble.

4. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues by means of a polymerizing agent, the stepwhich comprises subjecting to polymerization an emulsion of such nitrilein a liquid in which the said nitrile is practically insoluble.

5. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues by means of a peroxide, the step whichcomprises subjecting to polymerization an emulsion of such'nitrile in aliquid in which the said nitrile is practically insoluble.

6. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues, the step which comprises introducing thesaid nitrile into a warmed aqueous liquid in which it is practicallyinsoluble while intensely mixing.

'7. In the production of polymerization products and articles therefromby polymerization of a nitrile of the group consisting of acrylic acidnitrile and its homologues, the step which comprises introducing thesaid nitrile into a warmed aqueous liquid in which it is practicallyinsoluble while intensely mixing, at least one of' the said reactioncomponents containing a small quantity of an'emulsifying agent.

8. A process which comprises emulsifying acrylic acid nitrile and thenpolymerizing said nitrile.

. 9. A homogeneous, practically odorless polymerization productcomprising an alkyl ester of the group consisting of the alkyl esters ofacrylic acid and its homologues, emulsion-interpolymerized with acrylicnitrile, which polymerization product is substantially free frommonomeric compounds.

HANS

CLAUS

